The invention relates to a device for testing elongated objects, particularly wires, which may possibly have cross-sectional irregularities, with a rotary test head through which passes an object having at least one probe, more particularly in the form of an eddy current probe, on partly movable probe holding means and guided on circular probe paths around the object and, in the case of a rotating test head, externally operable switching or indexing device for modifying the radial spacing between the object and the probe. The invention more particularly relates to the problem of protecting sensitive probes with high rotation speeds guided close to the surface of an object passing through the test head when cross-sectional irregularities occur against contact with the object and therefore against destruction, in that they are moved back in good time and rapidly from a testing position near the object into a raised position further away from the object. Particularly in the case of cross-sectional irregularities with a limited axial extension, such as occur e.g. in the form of weld beads or sharp-edged shoulders in the case of welded wires in continuously operated wire drawing plants, the probes, after the test head has passed through the critical areas of the object, are to be returned with high reproduction accuracy into the testing position near the object.